A core network operator provides its telecommunications services to user equipments, such as, e.g. mobile phones, etc., through a Public Land Mobile Network, (PLMN). A PLMN typically comprises a Radio Access Network (RAN) and a Core Network (CN). Conventionally, a single operator provides its telecommunications services to its subscribers) via its own RAN and CN networks.
A Shared Network makes it possible for operators to share parts of their RAN or CN networks. This may be beneficial in order to decrease deployment costs and expenditures, but also helps to alleviate the environmental footprint left by system deployment.
A few examples of possible SN configurations for multiple PLMNs are illustrated in FIG. 1. In FIG. 1, the hatched boxes represent operator A's nodes or resources. The dotted boxes represent operator B's nodes or resources. The boxes with vertical lines represent shared nodes or resources. The continuous lines in FIG. 1 represent control plane and user plane, and the dotted line represent user plane only. Note that FIG. 1 uses two operators, operator A and B, only as an example and that any other suitable number of operators are applicable. The six columns in FIG. 1 illustrate six different example embodiments of SN configurations. For each of the six possible SN configurations, the sharing of the Packet Data Network Gateway (PDN GW, PGW), Home Subscriber Server (HSS), applications, Serving GW (SGW), Mobility Management Entities (MME), evolved NodeB (eNB) and cell are shown in respective rows. Site Sharing is a network configuration in which a site or location for operator specific RAN network nodes, e.g. eNodeBs in a RAN, is shared between two or more CNs, i.e. two or more operators. Each network operator has its own separate core network, i.e. MME, SGW, PDN GW, HSS, etc. in site sharing. A Geographical Split Network is a network configuration in which network operators share networks by allowing national roaming in their respective coverage areas. A Gateway Core Network (GWCN) is a network configuration in which both RAN, i.e. eNB, and MME is shared by two or more network operators; the core network parts, i.e. SGWs, PDN GW, HSS, etc. are located in each network operators own network. In a Roaming Network (RN) configuration, two or more operators share the RAN node, i.e. eNB. A Multiple Operator Core Network (MOCN) is a network configuration in which two or more network operators share a RAN, i.e. eNB; however, each network operator has its own separate core network, i.e. MME, SGW, PDN GW, HSS, etc.
MORAN (or “Split in the eNodeB”) is a network configuration in which, in addition to sharing a RAN network node, i.e. eNB, the resources of the RAN network node may be split for two or more network operators. In MORAN, each network operator has its own separate core network, i.e. MME, SGW, PDN GW, HSS, etc.
However, it should be noted that no matter which of the network configurations that are deployed, the PLMNs to which a cell belongs are given in the system information which is broadcast in each cell. A cell belongs always to at least one PLMN.
Furthermore, a shared network cell is considered to belong to all PLMNs given in the system information.
As more and more operators are interested in sharing RAN networks by, for example, owning different frequencies/cells, a fully incorporated MORAN network configuration is becoming increasingly interesting.
However, as the standard Evolved-Universal Terrestrial Radio Access (E-UTRA) Radio Resource Control (RRC) protocol specification, 3rd Generation Partnership Project (3GPP) Technical Specification (TS) 36.331, specifies requirements on the primary PLMN identity in the eNodeB, this may cause difficulties in configuring different PLMN identities for different frequencies/cells in order to obtain a MORAN network configuration.
Furthermore, different PLMN identities for different frequencies/cells in an eNodeB may need different S1 connections between the eNodeB and one MME on the frequency/cell level instead of on the eNodeB level. This further adds complexity when attempting to obtain a MORAN network configuration.